Not an X5 but help needed

[Themoog]

Hi all. My daughters boyfriend has an 07 E90 320d that keeps getting the trifecta on the dash but goes away after 5 min of running the engine.
I've scanned it with my c110 and most of the faults are low voltage to certain things.
The battery and alternator were replaced last October as if someone was chasing down a fault.
It's got one of those regulator things on top of the battery - could that be at fault? Any ideas? What are they even there for?
When the battery was replaced apparently the garage said that it didn't need coding to the car but I think it should.
I had a 2003 E53 and that battery had to be coded buy my 2001 E53 does not.
If anyone has any ideas please say.